Refrigerator and method for controlling operation of the same

ABSTRACT

Disclosed are a refrigerator, having a main body in which a first storage compartment and a second storage compartment having different preset storage temperatures are formed, and a compressor and a condenser to refrigerate each storage compartment, the refrigerator including: first and second evaporators corresponding to the first storage compartment and the second storage compartment, respectively; a first refrigerant tube connecting sequentially the compressor, the condenser and the first and second evaporators in series; a second refrigerant tube diverged from the first refrigerant tube at a front end of the first evaporator and connected to a front end of the second evaporator; and a 2-way switching valve provided between a diverging point of the second refrigerant tube and the first evaporator and closing/opening the first refrigerant tube.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Application No. 10-2005-0089038, filed on Sep. 24, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a refrigerator and a method for controlling an operation of the same, and more particularly, to a refrigerator including two storage compartments with preset storage temperatures which differ from each other and two evaporators provided corresponding to the respective storage compartments, and a method for controlling an operation of the same.

2. Description of the Related Art

In general, the refrigerator is an apparatus for storing food at a lower temperature and includes a refrigerating compartment in which the food is stored at a temperature that is above a freezing temperature; a freezing compartment in which the food is stored at a temperature that is below a freezing temperature; doors to open and close the refrigerating compartment and the freezing compartment; and a refrigerating system to cool the refrigerating compartment and the freezing compartment.

The refrigerating system includes a compressor, a condenser, a decompressing unit and an evaporator. In recent, there is an instance where two evaporators are provided for supplying independently cooling air to the refrigerating compartment and the freezing compartment.

FIG. 1 shows one example of the independent cooling type refrigerating system including the refrigerating compartment provided with the independent evaporator and the freezing compartment provided with the independent evaporator.

Referring to FIG. 1, the refrigerating system 101 of the conventional refrigerator includes a compressor 111; a condenser 112; decompressing units 161, 162 and 163; a first evaporator 141 provided corresponding to a first storage compartment 140 having a relatively high temperature and a second evaporator 151 provided corresponding to a second storage compartment 150 having a relatively low temperature; a main refrigerant tube 171 connecting sequentially the above members in series; a branch refrigerant tube 175 diverged from a front end of the first evaporator 141 and connected to a front end of the second evaporator 151; and a three-way valve 180 provided at a diverging point of the branch refrigerant tube 175 and opening and closing selectively the main refrigerant tube 171 and the branch refrigerant tube 175.

In the conventional refrigerator having the configuration as described above, in a case that the first storage compartment 140 and the second storage compartment 150 are simultaneously refrigerated, the main refrigerant tube 171 is opened and the branch refrigerant tube 175 is closed to make the refrigerant circulate in the compressor 111-the condenser 112-the 3-way valve 180-the first decompressing unit 161-the first evaporator 141-the second decompressing unit 162-the second evaporator 151-the compressor 111 in order. Also, in a case that only the second storage compartment 150 is refrigerated, the main refrigerant tube 171 is closed and the branch refrigerant tube 175 is opened to make the refrigerant circulate in the compressor 111-the condenser 112-the second decompressing unit 162-the second evaporator 151-the compressor 111 in order.

As described above, however, the conventional refrigerator has the drawback that, since the 3-way valve 180 is provided at a diverging point, the 3-way valve 180 should be always controlled in a case of refrigerating the first and second storage compartments 140 and 150 as well as a case of refrigerating only the second storage compartment 150.

Accordingly, a complicated control is needed for controlling the 3-way valve 180, and so a structure of the refrigerating system becomes complicate and the risk based on occurrence of mechanical troubles could be increased due to the complicated structure.

SUMMARY OF THE INVENTION

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

Accordingly, it is an aspect of the present invention to provide a refrigerator with two evaporators, which excludes a 3-way valve and can save a manufacturing cost and reduce risk due to occurrence of mechanical troubles by simplifying the structure and a control process for a refrigerating system.

The foregoing and/or other aspects of the present invention can be achieved by providing a refrigerator, having a main body in which a first storage compartment and a second storage compartment having different preset storage temperatures are formed, and a compressor and a condenser for refrigerating each storage compartment, the refrigerator including: first and second evaporators corresponding to the first storage compartment and the second storage compartment, respectively; a main refrigerant tube connecting sequentially the compressor, the condenser and the first and second evaporators in series; a second refrigerant tube diverged from the first refrigerant tube at a front end of the first evaporator and connected to a front end of the second evaporator; and a 2-way switching valve disposed between a diverging point of the second refrigerant tube and the first evaporator and to close/to open the main refrigerant tube.

According to an aspect of the invention, the refrigerator further includes an inside temperature sensor for sensing an inside temperature of the first storage compartment; and a control unit to control the 2-way switching valve such that the switching valve closes the main refrigerant tube when the inside temperature of the first storage compartment sensed by the inside temperature sensor reaches the preset storage temperature.

According to an aspect of the invention, the preset storage temperature of the first storage compartment is higher than the preset storage temperature of the second storage compartment.

According to an aspect of the invention, the refrigerator further includes a first decompressing unit disposed between the 2-way switching valve and the first evaporator and a second decompressing unit disposed between the branch point and the second evaporator.

According to an aspect of the invention, the refrigerator further includes a third decompressing unit disposed between the first evaporator and the second evaporator.

Still, another aspect of the present invention can be achieved by providing a method for controlling an operation of a refrigerator including a main body in which a first storage compartment and a second storage compartment are formed, and a compressor and a condenser for refrigerating each storage compartment, the method including: diverging a branch refrigerant tube from a main refrigerant tube, which connects sequentially the compressor, the condenser and first and second evaporators corresponding to the first and second storage compartments, at an front end of the first evaporator, the second refrigerant tube being connected the second evaporator; presetting storage temperatures of the first and second storage compartments such that a preset storage temperature of the first storage compartment is higher than a preset storage temperature of the second storage compartment; driving the compressor to perform a refrigerating operation; opening a 2-way switching valve disposed between a diverging point of the second refrigerant tube and the first evaporator; sensing an inside temperature of the first storage compartment; and closing the switching valve when the sensed inside temperature of the first storage compartment reaches the preset storage temperature of the first storage compartment.

According to an aspect of the invention, the method for controlling an operation of refrigerator further includes: sensing the inside temperature of the second storage compartment; and halting an operation of the compressor when the sensed inside temperature of the second storage compartment reaches the preset storage temperature.

Still, another aspect of the present invention can be achieved by providing a refrigerator having a main body in which n storage compartments having different preset storage temperatures, and a compressor and a condenser for refrigerating each storage compartment, including: n evaporators corresponding to n storage compartments, respectively; a main refrigerant tube connecting sequentially the compressor, the condenser and the n evaporators in series; n−1 branch refrigerant tubes diverged from the main refrigerant tube at a front end of the first evaporator and connected to a front end of any one of n−1 evaporators; and except the first one a n-way valve disposed at a rear side of a diverging point of the branch refrigerant tube connected to a front end of the evaporator, which corresponds to the storage compartment having a lowest preset storage temperature, among n−1 evaporators except the first evaporator, and closing/opening the main refrigerant tube and the other n−2 branch tubes.

According to an aspect of the invention, the refrigerator further includes n inside temperature sensors to sense inside temperatures of the n storage compartments; and a control unit to control the n-way valve according to a sensed each inside temperature sensor so as to prevent an inflow of the refrigerant into the evaporator corresponding to the storage compartment reaching the preset storage temperature.

According to an aspect of the invention, the n is 3 (three).

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects and advantages of the prevent invention will become apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompany drawings, in which:

FIG. 1 is a view showing a configuration of a refrigerating system of the conventional refrigerator;

FIG. 2 is a view showing a configuration of a refrigerating system of the refrigerator according to an aspect of the present invention;

FIG. 3 is a flow chart for illustrating a method for controlling an operation of the refrigerator according to an aspect of the present invention; and

FIG. 4 is a table showing the comparison result of the performances of the refrigerating systems of FIG. 1 and FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.

As shown in FIG. 2, a refrigerator according to an aspect of the present invention includes a main body (not shown) in which first and second storage compartments 40 and 50 are formed; a compressor 11 and a condenser 12 to refrigerate the first and second storage compartments 40 and 50; a first evaporator 41 corresponding to the first storage compartment 40 and a second evaporator 51 corresponding to the second storage compartment 50; a main refrigerant tube 71 connecting sequentially the compressor 11, the condenser 12, the first and second evaporators 41 and 51 in series; a branch refrigerant tube 75; and a switching valve 80.

Here, the refrigerator can further include inside temperature sensors 45 and 55 to sense inside temperatures of the first and second storage compartments 40 and 50, respectively, and a control unit (not shown) to control the 2-way switching valve 80 according to the sensed inside temperatures of the first and second storage compartments 40 and 50.

A main body (not shown) of the refrigerator is partitioned to provide the storage compartments 40 and 50 to store food. As occasion demands, the number of the storage compartments can be varied. In a case a plurality of storage compartments 40 and 50 are provided, the storage temperatures of the storage compartments 40 and 50 can be preset to differ from each other.

Hereinafter, as shown in FIG. 2, the refrigerator including two storage compartments 40 and 50 in which the preset storage temperatures differ from each other is described as the example. For convenience, the below description is made on the assumption that the storage temperature of the first storage compartment 40 is preset to be higher than the preset storage temperature of the second storage compartment 50.

The refrigerating system 1 includes the compressor 11 for raising the pressure of a refrigerant; the condenser 12 to condense the refrigerant compressed in the compressor 11; decompressing units 61, 62 and 63 to reduce a pressure of the condensed refrigerant; and the first and second evaporators 41 and 51.

The evaporators 41 and 51 corresponding to the storage compartments 40 and 50, respectively. While refrigerant is evaporated, the refrigerant absorbs heat around the evaporators 41 and 51, thereby cooling air. The evaporators 41 and 51 can differ in an evaporating capability from each other according to different preset storage temperature of the storage compartments 40 and 50. For example, if the storage temperature of the second storage compartment 50 is preset to be lower than the preset storage temperature of the first storage compartment 40, the second evaporator 51 can be provided to have the evaporating capability higher than that of the first evaporator 41. Cooling air produced in the evaporators 41 and 51 is supplied to the storage compartments 40 and 50 through cooling fans 43 and 53 provided corresponding to the evaporators 41 and 51, respectively.

The decompressing units 61, 62 and 63 reduce the pressure of the condensed refrigerant to be supplied to the evaporators 41 and 51. For example, capillary tubes or expansion valves can be provided as the decompressing units 61, 62 and 63.

A plurality of the decompressing units 61, 62 and 63 can be disposed between the condenser 12 and one of the evaporators 41 and 51 and between the evaporators 41 and 51. In this case, the decompressing units 61, 62 and 63 can be different in resistance from each other. Each evaporating capability of the decompressing units 61, 62 and 63 is in proportion to the resistance thereof. In a case that a plurality of refrigerant tubes are opened, a greater deal of the refrigerant is flowed in the refrigerant tube connected to the decompressing unit which having a lower resistance. Thus, a flow rate of the refrigerant can be distributed by disposing properly the decompressing units 61, 62 and 63 having the resistances which differ from each other.

In FIG. 2, for example, in a case that the refrigerant passed through the condenser 12 can enter both the main refrigerant tube 71 and the branch refrigerant tube 75 by opening the 2-way switching valve 80, if the resistance of the first decompressing unit 61 is less than that of the second compressing section 62, a greater deal of the refrigerant can be flowed in the main refrigerant tube 71.

The main refrigerant tube 71 forms a closed circuit of connecting sequentially the compressor 11, the condenser 12, the decompressing units 61, 62 and 63 and the first and second evaporators 41 and 51 in series, and so the refrigerant is flowed in the above order. An aspect of present invention, the order of the evaporators 41 and 51 connected in series to the main refrigerant tube 71 is determined according to the preset storage temperatures of the storage compartments 40 and 50 corresponding thereto. For example, the evaporators 41 and 51 are connected in series in descending order of the preset storage temperatures of the storage compartments 40 and 50. In this case, once the refrigerator is operated in the cooling mode, the first storage compartment 40 having a higher preset storage temperature first reaches the preset storage temperature. At this time, the refrigerant is flowed in the branch refrigerant tube 75 by closing the main refrigerant tube 71, and so only the second storage compartment 50 can be refrigerated selectively.

The branch refrigerant tube 75 is diverged between the condenser 12 and the first evaporator 41, and connected to a front end of the second evaporator 51. The branch refrigerant tube 75 bypasses the first evaporator 41, and so the refrigerant flowed in the branch refrigerant tube 75 can enter only the second evaporator 51. On the other hand, no valve for controlling a flow of the refrigerant to the branch refrigerant tube 75 can be provided on the branch refrigerant tube 75.

The 2-way switching valve 80 disposed between a diverging point of the branch refrigerant tube 75 and the first evaporator 41 to open/close the main refrigerant tube 71. The 2-way switching valve 80 can be provided to open/close completely the main refrigerant tube 71 or to adjust a flow rate of the refrigerant flowed in the main refrigerant tube 71. On the other hand, the user can operate manually the switching valve 80 or the switching valve can be controlled by a control unit (80).

The inside temperature sensors 45 and 55 are provided to sense the inside temperatures of the first and second storage compartments 40 and 50. In order to correspond each inside temperature sensor to each storage compartment, two inside temperature sensors, that is, the first inside temperature sensor 45 and the second inside temperature sensor 55 can be provided. Alternatively, three or more inside temperature sensors can be provided. Information about the inside temperatures of the storage compartments 40 and 50 sensed by the inside temperature sensors 45 and 55 is transmitted to the control unit 90.

The control unit (90) is disposed in the main body and compares the inside temperature of the first storage compartment 40 sensed by the first inside temperature sensor 45 with the preset storage temperature for the first storage compartment 40. Once the sensed inside temperature reaches the preset storage temperature, the control unit controls the 2-way switching valve 80 so as to prevent the refrigerant from flowing into the first evaporator 41. On the other hand, once the inside temperature of the second storage compartment 50 sensed by the second inside temperature sensor 55 reaches the preset storage temperature for the second storage compartment, the control unit 90 can halt an operation of the compressor 11.

An aspect of the present invention, the refrigerator is provided with two storage compartments 40 and 50 and corresponding two evaporators 41 and 51. However, the present invention is applicable to the refrigerator in which n (where, n is 3 or more) storage compartments are formed. For example, the refrigerator includes n storage compartments formed in the main body, n evaporators one-to-one corresponding to the storage compartments, the main refrigerant tube 71 connecting the n evaporators in series and n−1 branch refrigerant tubes 75 diverged from the main refrigerant tube at a front end of the first one of the n evaporators which are connected to each other in series and connected to an front end of any one of n−1 evaporators except the first one. An n-way valve is positioned at a rear side of a diverging point of the branch refrigerant tube 75 connected to a front end of the evaporator corresponding to the storage compartment having a lowest preset storage temperature. In general, in a case that n storage compartments are connected to each other in series, the storage compartments are connected in descending order of the preset storage temperatures, and so the n-way valve is provided at a rear side of a diverging point of the branch refrigerant tube 75 connected to a front end of the last evaporator. Accordingly, in a case 3 storage compartments are provided, the 3-way valve is disposed at a rear side of a diverging point of the second branch refrigerant tube connected to a front end of the third evaporator to open and close the main refrigerant tube and the first branch refrigerant tube.

Below, the method for controlling an operation of the refrigerator according to an aspect of the present invention is described in detail with reference to FIG. 3.

First of all, the refrigerator according to an aspect of the present invention includes the first and second storage compartments 40 and 50 formed therein; the first evaporator 41 corresponding to the first storage compartment 40 and the second evaporator 51 corresponding to the second storage compartment 50; the main refrigerant tube 71 to which the first and second evaporators 41 and 51 are connected sequentially in series; the branch refrigerant tube 75 diverged from the main refrigerant tube at a front end of the first evaporator 41 and connected to a front end of the second evaporator 51; and the 2-way switching valve 80 disposed between a diverging point of the branch refrigerant tube 75 and the first evaporator 41.

First, the storage temperatures of the first storage compartment 40 and the second storage compartment 50 are preset. The storage compartment 40 can have the preset storage temperature which differs from that of the second storage compartment 50. For example, the storage temperatures can be preset such that the preset storage temperature T1 of the first storage compartment 40 is higher than the preset storage temperature T2 (T1>T2) of the second storage compartment 50 at operation S11.

The case of refrigerating simultaneously the first storage compartment 40 and the second storage compartment 50 is described as follows.

The compressor 11 is driven to refrigerate the first and second storage compartments 40 and 50 at operation S12, and the inside temperatures of the first and second storage compartments 40 and 50 are sensed by the inside temperature sensors 45 and 55 at operation S13.

In the early state at which a refrigerating operation is initiated by driving the compressor 11, the 2-way switching valve 80 is opened so as to allow the refrigerant to flow sequentially in the first evaporator 41 and the second evaporator 51 through the main refrigerant tube 71 at operation S14. In this case, once the 2-way switching valve 80 is opened, both the main refrigerant tube 71 and the branch refrigerant tube 75 become opened, and so the refrigerant passed through the condenser 12 can be flowed into both the main refrigerant tube 71 and the branch refrigerant tube 75. However, since the storage temperature of the first storage compartment 40 is higher than that of the second storage compartment, an evaporation pressure in the first evaporator 41 is relatively high so that most refrigerant enters the main refrigerant tube 71. Accordingly, although the minimum of the refrigerant is entered to the second evaporator 51 through the branch refrigerant tube 75, such refrigerant little affects the performance of the refrigerator and the energy consumption.

Also, in a case that the resistance of the second decompressing unit 62 disposed on the branch refrigerant tube 75 is larger than the sum of the resistances of the first and third decompressing units 61 and 63 disposed on the main refrigerant tube 71, it is possible to make a greater deal of the refrigerant flow into the main refrigerant tube 71.

The control unit 90 compares the inside temperature of the first storage compartment 40 sensed by the first inside temperature sensor 45 with the preset storage temperature of the first storage compartment 40 at operation S15. If the inside temperature of the first storage compartment 40 reaches the preset storage temperature of the first storage compartment, the control unit closes the switching valve 80 at operation S16 so as to prevent an inflow of the refrigerant into the first evaporator 41. Therefore, the refrigerant is directly flowed to the second evaporator 51 through the branch refrigerant tube 75.

Next, if the second storage compartment 50 sensed by the second inside temperature sensor 55 reaches the preset storage temperature of the second storage compartment 50 at operation S17, the control unit 90 halts the operation of the compressor 11 to stop the refrigerating operation at operation S18.

FIG. 4 is a table showing the comparison result of the performances of the conventional refrigerating system shown in FIG. 1 and the refrigerating system according to an aspect of the present invention shown in FIG. 2. The results shown in FIG. 4 is obtained after the refrigerating operation is performed under the condition of an external temperature of 32° C., a humidity of 75%, a preset storage temperature of the second storage compartment of −20° C. and a preset storage temperature of the first storage compartment 40 of 1°C.

Here, the operation ratio refers to a proportion of the time for which the compressor 11 is driven to the reference time for which the refrigerating operation is performed. It is known from table shown in FIG. 4 that the operation ratio obtained by using only the switching valve 80 is substantially same as that obtained by using the three-way valve and there is no difference in the power consumption between the case of using the 2-way switching valve and the case of using the three-way valve.

Accordingly, the refrigerator and the method to control an operation of the same can refrigerate selectively the first storage compartment 40 or the second storage compartment 50 by the 2-way switching valve 80 provided between a diverging point and the first evaporator 41 without using the three-way valve.

Therefore, there is no need to use the three-way valve which is relatively expense as compared with the 2-way switching valve 80, and so the manufacturing cost can be saved. Also, there is no need to construct the complicated control system required to control the three-way valve so that the configuration of the refrigerating system and the process to control the refrigerating system become simplified, and so the risk due to occurrence of mechanical troubles could be reduced.

According to the refrigerator and the method to control an operation of the same according to the present invention as described above, by using only the switching valve disposed at the main refrigerant tube, the operation effect of the refrigerator such as an operation of the refrigerating compartment under high humidity and a selective refrigeration of each storage compartment which are the same as that obtained by using the three-way valve can be obtained. Accordingly, there is no need to use the three-way valve, and so the manufacturing cost can be saved, and a configuration of the refrigerating system and a procedure to control the refrigerating system are simplified so that the risk due to occurrence of the mechanical troubles could be reduced.

Although a few exemplary embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents. 

1. A refrigerator, having a main body in which a first storage compartment and a second storage compartment having different preset storage temperatures are formed, and a compressor and a condenser to refrigerate each storage compartment, the refrigerator comprising: first and second evaporators corresponding to the first storage compartment and the second storage compartment, respectively; a first refrigerant tube connecting sequentially the compressor, the condenser and the first and second evaporators in series; a second refrigerant tube diverged from the first refrigerant tube at a front end of the first evaporator and connected to a front end of the second evaporator; and a switching valve disposed between a diverging point of the branch refrigerant tube and the first evaporator and closing/opening the first refrigerant tube.
 2. The refrigerator according to claim 1, further comprising an inside temperature sensor to sense an inside temperature of the first storage compartment; and a control unit to control the switching valve such that the switching valve closes the first refrigerant tube when the inside temperature of the first storage compartment sensed by the inside temperature sensor reaches the preset storage temperature.
 3. The refrigerator according to claim 2, wherein the preset storage temperature of the first storage compartment is higher than the preset storage temperature of the second storage compartment.
 4. The refrigerator according to claim 3, further comprising a first decompressing unit disposed between the switching valve and the first evaporator and a second decompressing unit disposed between the branch point and the second evaporator.
 5. The refrigerator according to claim 4, further comprising a third decompressing unit disposed between the first evaporator and the second evaporator.
 6. The refrigerator according to claim 1, wherein the switching valve is a 2-way switch valve.
 7. A method to control an operation of a refrigerator comprising a main body in which a first storage compartment and a second storage compartment are formed, a second refrigerant tube from a first refrigerant tube, which connects sequentially the compressor, the condenser and first and second evaporators corresponding to the first and second storage compartments, at an front end of the first evaporator, the branch refrigerant tube being connected the second evaporator; and a compressor and a condenser for refrigerating each storage compartment, the method comprising: presetting storage temperatures of the first and second storage compartments such that a preset storage temperature of the first storage compartment is higher than a preset storage temperature of the second storage compartment; driving the compressor to perform a refrigerating operation; opening a switching valve provided between a diverging point of the second refrigerant tube and the first evaporator; sensing an inside temperature of the first storage compartment; and closing the switching valve when the sensed inside temperature of the first storage compartment reaches the preset storage temperature of the first storage compartment.
 8. The method to control an operation of refrigerator according to claim 7, further comprising: sensing the inside temperature of the second storage compartment; and halting an operation of the compressor when the sensed inside temperature of the second storage compartment reaches the preset storage temperature of the second storage compartment.
 9. The method to control an operation of refrigerator according to claim 7, wherein the switching valve is a 2-way switching valve.
 10. A refrigerator having a main body in which n storage compartments having different preset storage temperatures are formed, and a compressor and a condenser to refrigerate each storage compartment, comprising: n evaporators corresponding to n storage compartments, respectively; a main refrigerant tube connecting sequentially the compressor, the condenser and the n evaporators in series; n−1 branch refrigerant tubes diverged from the main refrigerant tube at a front end of the first evaporator and connected to a front end of any one of n−1 evaporators; and except the first one a n-way valve provided at a rear side of a diverging point of the branch refrigerant tube connected to a front end of the evaporator, which corresponds to the storage compartment having a lowest preset storage temperature, among n−1 evaporators except the first evaporator, and closing/opening the main refrigerant tube and the other n−2 branch tubes.
 11. The refrigerator according to claim 10, further comprising n inside temperature sensors to sense inside temperatures of the n storage compartments; and a control unit to control the n-way valve according to a sensing result of each inside temperature sensor so as to prevent an inflow of the refrigerant into the evaporator corresponding to the storage compartment reaching the preset storage temperature.
 12. The refrigerator according to claim 11, wherein the n is 3 (three).
 13. A method to control an operation of a refrigerator comprising a main body in which a first storage compartment and a second storage compartment are formed, and a compressor and a condenser for refrigerating each storage compartment, a second refrigerant tube from a first refrigerant tube, which connects sequentially the compressor, the condenser and first and second evaporators corresponding to the first and second storage compartments, at an front end of the first evaporator, the second refrigerant tube being connected the second evaporator; the method comprising: driving the compressor; and flowing a refrigerant into the first refrigerant tube and the second refrigerant tube simultaneously to operate the first and the second storage compartments at the same time.
 14. The method of claim 13, further comprises sensing an inside temperature of the first storage compartment; and closing switching valve to stop flowing the refrigerant to the first refrigerant tube when the sensed the inside temperature of the first storage compartment is lower than a predetermined temperature of the first storage compartment.
 15. The method of claim 14, further comprises: sensing an inside temperature of the second storage compartment; and halting an operation of the compressor when the sensed the inside temperature of the first storage compartment is lower than a predetermined temperature of the second storage compartment. 